German Railways (DB) operates a train from Frankfurt am Main to Boppard hourly. Tickets cost $30 - $45 and the journey takes 1 h 31 min. Alternatively, FlixBus operates a bus from Frankfurt am Main to Boppard twice daily. Tickets cost $8 - $14 and the journey takes 2 h 25 min. 2 other operators also service this route.
From Frankfurt(Main)Hbf train to Boppard Hbf. 1 h 31 min 30€. From Frankfurt, Frankfurt central station bus to Koblenz Hbf then train to Boppard Hbf. 2 h 53 min 22€. From Frankfurt am Main drive to Boppard. 1 h 16 min 16€.